Park’s Classification of Anorectal
Type 1 - Intersphincteric (45%)
Type 2 -Transphincteric
Type 3 – Suprasphincteric
Type 4 - Extrasphincteric
Intersphincteric – through the dentate line to anal verge,
tracking along the intersphincteric plane, ending in the
Transsphinteric – through the external sphincter into the
ischiorectal fossa, encompassing a portion of internal &
external sphincter ending in the skin.
Suprasphinteric – through the anal crypt & encircling the
entire sphincter ending in ischiorectal fossa.
Extrasphinteric – starting high in the anal canal, enclosing
the entire anal sphincter & ending in the skin.
Chronic drainage from
Pain with defecation
Systemic symptoms if
abscess gets infected.
Goodsall’s rule is a guideline for internal opening & path of
fistula track & aids in Rx.
Fistula can be described as anterior or posterior relating to a
line drawn in the coronal plane through ischial spines across
the anus - called transverse anal line.
Anterior fistulas - have a direct track into the anal canal.
Posterior fistulas - have a curved track with their internal
opening lying in the posterior midline of the anal canal.
An exception to the rule - anterior fistulas lying more than 3
cm. from the anus, which may have a curved track (similar to
posterior fistulas) that opens into the posterior midline of the
Goodsall's rule may not be
applicable when the fistula is
more than 3 cm from the anal
verge, as mostly these fistula are
If there are multiple anal fistulae,
the course would be similar to
that of posterior-opening fistulae
because of branching and
communication between these
• Exam under anesthesia (EUA)-
anoscopy, proctoscopy; assess for
internal opening and occult
– Injection of Hydrogen peroxide or
povidone iodine allows to visualize
bubbles at internal opening(s)
• Endo anal ultrasound
• MRI – gold std
Goals of Therapy
Drain local infection
Eradicate fistulous tract
Avoid recurrence while preserving native sphincter function
Advancement flaps & glues
lay open fistula tract, make incision over entire length of fistula
using probe as guide
intersphincteric fistula & trans-sphincteric fistulae involving
less than 30% of the voluntary musculature .
Avoided for anteriorly placed fistulae in women
Staged Fistulotomy – seton passed across the fistula & left in
place with tie
Fistula granulates & heals from above to close completely.
involves coring out of the fistula by diathermy cautery
Better for fistula that cross level of sphincters and the
presence of secondary extensions.
Post-op: sitz bath, antibiotics, analgesics, laxatives
non-absorbable, nondegenerative, comfortable.
Silk or linen ligature
m/c intersphincteric fistula.
Kept for 3 months replaced by rail road tecq.
loose setons: no tension, no intent to cut the tissue.
- for recurrent, post operative fistulas.
Uses of loose setons.
- For long-term palliation to avoid septic and painful exacerbations by
- before ‘advanced’ techniques (fistulectomy, advancement flap,
- staged fistulotomy
- preserve the external sphincter in trans-sphincteric fistulae.
Tight or cutting setons :
placed with the intention of cutting through the enclosed
Used if the fistula is in a high position and it passes through a
significant portion of the sphincter muscle
high fistula eradication rates a/w fistulotomy.
Minimising sphincter dysfunction due to least scar formation.
cheese wiring through ice -such that the divided muscles do not
site of the fistula track is replaced by a thin line of fibrosis as it
is brought down.
Endorectal advancement flaps:-coring out of the entire
track; and closure of the communication with the anal lumen
with an adequately vascularised flap consisting of mucosa and
internal sphincter, sutured without tension to the anoderm.
Success rate is variable.
high recurrence rates are directly related to previous attempts to
correct the fistula.
Fibrin plugs & Glues :
Plugging the fistula with a device made from small intestinal
The fistula plug is positioned from the inside of the anus with
Success rate with this method is as high as 80%.
Fistula plug procedure requires hospitalization for only about
- Fibrin glue is currently the only non-surgical option for
- The fibrin glue is injected into the fistula to seal the tract.
The glue is injected through the opening of the fistula, and
the opening is then stitched closed.
-long-term results for this treatment method are poor.
Ligation of intersphinteric fistula tract procedure.
Based on secure closure of the internal opening and removal
of infected cryptoglandular tissue through the
Essential steps -
incision at the intersphincteric groove
identification of the intersphincteric tract
ligation of intersphincteric tract close to the internal opening
and removal of intersphincteric tract
scraping out all granulation tissue in the rest of the fistulous
suturing of the defect at the external sphincter muscle